I'm scared
 

I was doing so well.. the best I have ever done before no self harm for 6 months then boom the past haunts me and it happened, im scared because I'm on a new relationship and she knows I've done it before and made me promise I would talk to her first and I couldn't do it I couldn't talk to anyone now I'm more scared than ever

Slip-ups happen. 6 months without self-harming is so great, but it is ok to slip-up. It doesn't mean you're back at square one, you haven't failed or anything, it's just a slip-up. These things happen, and that is ok.

It sounds like a lot of pressure on you feeling that you 'should' have talked to your friend first. Can you explain to her that sometimes you find that difficult, and that it would be helpful to talk even if you've already done it or not managed to reach out before?